Many students ask me how do I do this or that in MATLAB. So I thought why not have a small series of my next few blogs do that. In this blog I show you how to integrate a continuous function.

The MATLAB program link is here.

The HTML version of the MATLAB program is here.

___________________________________________

%% HOW DO I DO THAT IN MATLAB SERIES?

% In this series, I am answering questions that students have asked

% me about MATLAB. Most of the questions relate to a mathematical

% procedure.

%% TOPIC

% How do I integrate a continuous function?

%% SUMMARY

% Language : Matlab 2008a;

% Authors : Autar Kaw;

% Mfile available at

% http://numericalmethods.eng.usf.edu/blog/integration.m;

% Last Revised : March 28, 2009;

% Abstract: This program shows you how to integrate a given function.

clc

clear all

%% INTRODUCTION

disp(‘ABSTRACT’)

disp(‘ This program shows you how to integrate’)

disp(‘ a given function ‘)

disp(‘ ‘)

disp(‘AUTHOR’)

disp(‘ Autar K Kaw of http://autarkaw.wordpress.com’)

disp(‘ ‘)

disp(‘MFILE SOURCE’)

disp(‘ http://numericalmethods.eng.usf.edu/blog/integration.m’)

disp(‘ ‘)

disp(‘LAST REVISED’)

disp(‘ March 29, 2009′)

disp(‘ ‘)

%% INPUTS

% Integrate exp(x)*sin(3*x) from x=2.0 to 8.7

% Define x as a symbol

syms x

% Assigning the function to be differentiated

y=exp(x)*sin(3*x);

% Assigning the lower limit

a=2.0;

% Assigning the upper limit

b=8.7;

%% DISPLAYING INPUTS

disp(‘INPUTS’)

func=[' The function is to be integrated is ' char(y)];

disp(func)

fprintf(‘ Lower limit of integration, a= %g’,a)

fprintf(‘\n Upper limit of integration, b= %g’,b)

disp(‘ ‘)

disp(‘ ‘)

%% THE CODE

% Finding the integral using the int command

% Argument 1 is the function to be integrated

% Argument 2 is the variable with respect to which the

% function is to be integrated – the dummy variable

% Argument 3 is the lower limit of integration

% Argument 4 is the upper imit of integration

intvalue=int(y,x,a,b);

intvalue=double(intvalue);

%% DISPLAYING OUTPUTS

disp(‘OUTPUTS’)

fprintf(‘ Value of integral is = %g’,intvalue)

disp(‘ ‘)

_________________________________________________________

This post is brought to you by Holistic Numerical Methods: Numerical Methods for the STEM undergraduate at http://numericalmethods.eng.usf.edu, the textbook on Numerical Methods with Applications available from the lulu storefront, and the YouTube video lectures available at http://numericalmethods.eng.usf.edu/videos and http://www.youtube.com/numericalmethodsguy

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Thank you very much for this brief tutorial. The last two steps had worried me so much.